Electronic article surveillance (EAS) systems are well known in the art and are used for inventory control and to prevent theft and similar unauthorized removal of articles from a controlled area. Typically, in such systems a system transmitter and a system receiver are used to establish a surveillance zone that must be traversed by any articles being removed from the controlled area.
An EAS tag is affixed to each article and includes a marker or sensor adapted to interact with a signal being transmitted by the system transmitter into the surveillance zone. This interaction causes a further signal to be established in the surveillance zone which further signal is received by the system receiver. Accordingly, upon movement of a tagged article through the surveillance zone, a signal will be received by the system receiver, identifying the unauthorized presence of the tagged article in the zone. An alarm may thereafter be triggered by the system receiver, on the EAS tag, or both, to further expose the unauthorized presence of the tagged article in the surveillance zone.
Certain types of EAS tags have been designed to be reusable and accordingly include releasable attachment devices for affixing the tags to the articles. Such attachment devices are further designed to be releasable by authorized personnel only so that unauthorized removal of a tag from its article is avoided. To this end, many attachment devices are made releasable only through the use of an associated special tool or detaching mechanism. Clever thieves, however, have developed methods to defeat some EAS tags.